package 剑指Offer1;

public class _27合并两个排序的链表 {
    public class ListNode {
       int val;
       ListNode next;
       ListNode(int x) { val = x; }
   }

    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1 == null && l2 == null) return null;
        if(l1 == null) return l2;
        if(l2 == null) return l1;
        ListNode newHead = new ListNode(0);
        ListNode temp = newHead;

        while(l1!=null && l2!=null){
            if(l1.val<l2.val){
                temp.next = l1;
                l1 = l1.next;
            }else{
                temp.next = l2;
                l2 = l2.next;
            }
            temp = temp.next;
        }

        if(l1!=null){
            temp.next = l1;
        }else{
            temp.next = l2;
        }
        return newHead.next;
    }
}
